Abstract: This system utilizes a PC industrial control computer to convert the pattern information of jacquard fabrics into control information for the loom through information processing. It then uses program control to coordinate the electromagnetic needle selection mechanism with the mechanical movement of the loom to achieve jacquard weaving. The design fully utilizes the programmable logic device (CPLD) ATF1508AS to complete various logic functions, resulting in a simple, high-speed, and stable control system. Keywords: PC104; program control; programmable logic device (CPLD); electromagnetic needle selection 1 Introduction Jacquard systems are widely used in China's textile industry. However, traditional jacquard systems mostly use microcontrollers as control units. Due to the limitations of the microcontroller's structure and function, the system's data processing speed is slow, its anti-interference capability is poor, and various working and operating states are often only displayed through digital tubes or LEDs, resulting in unintuitive display results and causing significant inconvenience to operators. To improve system performance and increase weaving efficiency, we designed this control system. This design uses a PC104 industrial computer as the control unit, which improves the anti-interference capability of the entire system and increases the data processing speed several times over. It also uses C language programming, and various information statuses are directly displayed on the LCD screen using Chinese characters, providing excellent human-machine interaction. 2 System Scheme and Structure The system mainly consists of three parts: a PC104 adapter card, an electromagnetic needle selection interface, and software design and programming. The PC104 adapter card mainly drives, converts, and sends the loom control information sent by the industrial computer to the electromagnetic needle selection interface, while also receiving various external control commands, such as: stop, reverse, weft finding, etc. [1]. The electromagnetic needle selection interface sends jacquard control information to the needle circuit and reads the verification status, mechanical OE signal, etc. Software program functions: analyzes the jacquard fabric pattern information and converts it into loom control information; analyzes the various statuses read from the bus and realizes human-machine interaction. 2.1 Design of PC104 Adapter Card The adapter card unit is based on the parallel port expansion chip 8255A. The main components include: decoding circuit, driver circuit, parallel port expansion, input and output interface, etc. The decoding circuit mainly uses the programming of GAL16V8 chip to perform logical combination of address bus to determine the address of 8255A (0x208～0x20b). The functions of the three expansion ports of 8255A are defined as follows: PA port is defined as the basic input port, used to read external manual control signals. PB port is occupied by PB0 as OE signal input, PB1 as verification input terminal, and PB2 as mechanical maintenance signal. PC port is defined as the basic output port, PC4 as clock terminal, PC5 as data signal, PC6 as STB signal, and PC7 as stop signal [2]. 2.2 Design and Structure of Electromagnetic Pin Selection Interface The electromagnetic pin selection interface uses CPLD device ATF1508AS to connect all signals in the interface, making hardware debugging software-based, and making it extremely convenient to modify circuit timing and combinational logic. The timing and logic relationships within the device are all implemented using AHDL programming [3, 4]. The internal design of the ATF1508AS can be divided into four modules: automatic maintenance circuit, needle selection signal, and shutdown mode. During maintenance, the ATF1508AS divides the system clock to obtain the internal OE and clock signal, which are provided to the needle circuit. The maintenance data is sent to the needle circuit for detection and maintenance through the internal clock. During normal operation, the ATF1508AS outputs the data, clock, and STB jacquard signal from the adapter card to the needle circuit. The OE synthesis module synthesizes the forward mechanical OE1, reverse mechanical OE2, and needle position OE3 according to the weaving process into a final valid OE and transmits it to the adapter card. The verification and judgment module performs logical judgment on the data returned by the needle circuit and the verification bit to set the verification status of the adapter card to determine whether to resend data or provide a fault indication. The circuit principle is shown in Figure 2. The DB25 jack serves as the information exchange channel between the adapter card interface and the electromagnetic needle selection interface to transmit various information—jacquard data, clock, STB, stop signal, etc. The ATF1508AS determines whether to provide the internal OE, data, and clock signals to the needle circuit for detection and maintenance, or to output the jacquard signal from the adapter card's transmitter to the needle circuit for jacquard weaving, by reading the state of the DIP switch S1. If jacquard weaving is to be performed, the forward mechanical OE1, reverse mechanical OE2, and needle position OE3 are logically synthesized according to the weaving process to provide a valid OE to the adapter card. 3. Software Design and Flow The jacquard data transmission timing is shown in Figure 3. The timing diagram shows that in the OE invalid region (5/6 OE), the program can send a clock signal and output jacquard information at the corresponding data bit. If the verification is correct, the STB bit is set, and the data is output to the needle circuit, waiting for a valid OE to proceed with jacquard weaving. If the verification result is a data transmission error, the data is sent again for verification. If data transmission fails three times consecutively, the machine will stop and display a data transmission fault message. Each shuttle's data must be correctly transmitted within the OE invalid zone; otherwise, skipped or missed stitches will occur during weaving. Therefore, the OE cycle and the number of shuttle needles directly determine the longest data clock cycle. However, to improve the system's anti-interference capability and consider secondary transmissions due to data transmission failures, the clock cycle cannot be shortened indiscriminately. Therefore, the formula for calculating the clock cycle T is: T ≤ (5/6Toe)/3N, where Toe is the OE cycle (mechanical revolutions), and N is the number of needles per shuttle. The jacquard data transmission process is shown in Figure 4. In this design, the data clock cycle adopts an adaptive control method, automatically selecting a delay coefficient based on the amount of data per shuttle (N) to determine the clock cycle, thereby achieving optimal anti-interference while ensuring the system can correctly transmit data within the OE invalid zone. 4 Conclusion Field testing shows that this system can achieve a weaving speed of 500 shuttles/min for a 672-needle head. For a 1760-needle head, the knitting speed can reach 330 shuttles/min, which has a high production efficiency and stability. It has a user-friendly human-machine interface, which is convenient and intuitive to operate. At the same time, the adaptive design of the software makes this system applicable to heads with different needle counts, and also greatly improves the anti-interference ability of the system, which is in a leading position in China. 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